29708
|
1 |
(* Title: HOL/Library/Mapping.thy
|
|
2 |
Author: Florian Haftmann, TU Muenchen
|
|
3 |
*)
|
|
4 |
|
|
5 |
header {* An abstract view on maps for code generation. *}
|
|
6 |
|
|
7 |
theory Mapping
|
|
8 |
imports Map
|
|
9 |
begin
|
|
10 |
|
|
11 |
subsection {* Type definition and primitive operations *}
|
|
12 |
|
|
13 |
datatype ('a, 'b) map = Map "'a \<rightharpoonup> 'b"
|
|
14 |
|
|
15 |
definition empty :: "('a, 'b) map" where
|
|
16 |
"empty = Map (\<lambda>_. None)"
|
|
17 |
|
|
18 |
primrec lookup :: "('a, 'b) map \<Rightarrow> 'a \<rightharpoonup> 'b" where
|
|
19 |
"lookup (Map f) = f"
|
|
20 |
|
|
21 |
primrec update :: "'a \<Rightarrow> 'b \<Rightarrow> ('a, 'b) map \<Rightarrow> ('a, 'b) map" where
|
|
22 |
"update k v (Map f) = Map (f (k \<mapsto> v))"
|
|
23 |
|
|
24 |
primrec delete :: "'a \<Rightarrow> ('a, 'b) map \<Rightarrow> ('a, 'b) map" where
|
|
25 |
"delete k (Map f) = Map (f (k := None))"
|
|
26 |
|
|
27 |
primrec keys :: "('a, 'b) map \<Rightarrow> 'a set" where
|
|
28 |
"keys (Map f) = dom f"
|
|
29 |
|
|
30 |
|
|
31 |
subsection {* Derived operations *}
|
|
32 |
|
|
33 |
definition size :: "('a, 'b) map \<Rightarrow> nat" where
|
|
34 |
"size m = (if finite (keys m) then card (keys m) else 0)"
|
|
35 |
|
29814
|
36 |
definition replace :: "'a \<Rightarrow> 'b \<Rightarrow> ('a, 'b) map \<Rightarrow> ('a, 'b) map" where
|
|
37 |
"replace k v m = (if lookup m k = None then m else update k v m)"
|
|
38 |
|
29708
|
39 |
definition tabulate :: "'a list \<Rightarrow> ('a \<Rightarrow> 'b) \<Rightarrow> ('a, 'b) map" where
|
|
40 |
"tabulate ks f = Map (map_of (map (\<lambda>k. (k, f k)) ks))"
|
|
41 |
|
29826
|
42 |
definition bulkload :: "'a list \<Rightarrow> (nat, 'a) map" where
|
|
43 |
"bulkload xs = Map (\<lambda>k. if k < length xs then Some (xs ! k) else None)"
|
|
44 |
|
29708
|
45 |
|
|
46 |
subsection {* Properties *}
|
|
47 |
|
|
48 |
lemma lookup_inject:
|
|
49 |
"lookup m = lookup n \<longleftrightarrow> m = n"
|
|
50 |
by (cases m, cases n) simp
|
|
51 |
|
|
52 |
lemma lookup_empty [simp]:
|
|
53 |
"lookup empty = Map.empty"
|
|
54 |
by (simp add: empty_def)
|
|
55 |
|
|
56 |
lemma lookup_update [simp]:
|
|
57 |
"lookup (update k v m) = (lookup m) (k \<mapsto> v)"
|
|
58 |
by (cases m) simp
|
|
59 |
|
|
60 |
lemma lookup_delete:
|
|
61 |
"lookup (delete k m) k = None"
|
|
62 |
"k \<noteq> l \<Longrightarrow> lookup (delete k m) l = lookup m l"
|
|
63 |
by (cases m, simp)+
|
|
64 |
|
|
65 |
lemma lookup_tabulate:
|
|
66 |
"lookup (tabulate ks f) = (Some o f) |` set ks"
|
|
67 |
by (induct ks) (auto simp add: tabulate_def restrict_map_def expand_fun_eq)
|
|
68 |
|
29826
|
69 |
lemma lookup_bulkload:
|
|
70 |
"lookup (bulkload xs) = (\<lambda>k. if k < length xs then Some (xs ! k) else None)"
|
|
71 |
unfolding bulkload_def by simp
|
|
72 |
|
29708
|
73 |
lemma update_update:
|
|
74 |
"update k v (update k w m) = update k v m"
|
|
75 |
"k \<noteq> l \<Longrightarrow> update k v (update l w m) = update l w (update k v m)"
|
|
76 |
by (cases m, simp add: expand_fun_eq)+
|
|
77 |
|
29814
|
78 |
lemma replace_update:
|
|
79 |
"lookup m k = None \<Longrightarrow> replace k v m = m"
|
|
80 |
"lookup m k \<noteq> None \<Longrightarrow> replace k v m = update k v m"
|
|
81 |
by (auto simp add: replace_def)
|
|
82 |
|
29708
|
83 |
lemma delete_empty [simp]:
|
|
84 |
"delete k empty = empty"
|
|
85 |
by (simp add: empty_def)
|
|
86 |
|
|
87 |
lemma delete_update:
|
|
88 |
"delete k (update k v m) = delete k m"
|
|
89 |
"k \<noteq> l \<Longrightarrow> delete k (update l v m) = update l v (delete k m)"
|
|
90 |
by (cases m, simp add: expand_fun_eq)+
|
|
91 |
|
|
92 |
lemma update_delete [simp]:
|
|
93 |
"update k v (delete k m) = update k v m"
|
|
94 |
by (cases m) simp
|
|
95 |
|
|
96 |
lemma keys_empty [simp]:
|
|
97 |
"keys empty = {}"
|
|
98 |
unfolding empty_def by simp
|
|
99 |
|
|
100 |
lemma keys_update [simp]:
|
|
101 |
"keys (update k v m) = insert k (keys m)"
|
|
102 |
by (cases m) simp
|
|
103 |
|
|
104 |
lemma keys_delete [simp]:
|
|
105 |
"keys (delete k m) = keys m - {k}"
|
|
106 |
by (cases m) simp
|
|
107 |
|
|
108 |
lemma keys_tabulate [simp]:
|
|
109 |
"keys (tabulate ks f) = set ks"
|
|
110 |
by (auto simp add: tabulate_def dest: map_of_SomeD intro!: weak_map_of_SomeI)
|
|
111 |
|
|
112 |
lemma size_empty [simp]:
|
|
113 |
"size empty = 0"
|
|
114 |
by (simp add: size_def keys_empty)
|
|
115 |
|
|
116 |
lemma size_update:
|
|
117 |
"finite (keys m) \<Longrightarrow> size (update k v m) =
|
|
118 |
(if k \<in> keys m then size m else Suc (size m))"
|
|
119 |
by (simp add: size_def keys_update)
|
|
120 |
(auto simp only: card_insert card_Suc_Diff1)
|
|
121 |
|
|
122 |
lemma size_delete:
|
|
123 |
"size (delete k m) = (if k \<in> keys m then size m - 1 else size m)"
|
|
124 |
by (simp add: size_def keys_delete)
|
|
125 |
|
|
126 |
lemma size_tabulate:
|
|
127 |
"size (tabulate ks f) = length (remdups ks)"
|
|
128 |
by (simp add: size_def keys_tabulate distinct_card [of "remdups ks", symmetric])
|
|
129 |
|
29831
|
130 |
lemma bulkload_tabulate:
|
29826
|
131 |
"bulkload xs = tabulate [0..<length xs] (nth xs)"
|
29831
|
132 |
by (rule sym)
|
|
133 |
(auto simp add: bulkload_def tabulate_def expand_fun_eq map_of_eq_None_iff map_compose [symmetric] comp_def)
|
29826
|
134 |
|
29708
|
135 |
end |